1. Field of the Invention
This invention relates generally to disk storage for computer systems. In particular, it is directed to an array of asynchronously-operating disk drives that emulate a single logical disk drive.
2. Description of the Prior Art
Disk drives have long been popular mass storage devices. They provide a low cost solution to the problem of non-volatile data storage. Virtually all computer system manufacturers, therefore, provide for disk drives as system peripherals.
The major advantage of disk drives is low cost. This advantage is outweighed for some applications by the disadvantage of insufficient data transfer speed, particularly in supercomputer and other high performance computing environments such as the type manufactured by Cray Research, Inc., the assignee of the present invention. The problems facing a computer system user wishing to increase the data transfer rates of disk drives are not trivial. Up until now, most solutions have sought to incrementally enhance the performance of a single disk drive while retaining the disk drive's basic architecture.
Prior art disk drives are limited in their capacity and speed in transferring data. The prior art lacks high performance disk drives which achieve data transfer rates comparable to the speeds of currently available computers. Prior art disk drives are also limited in their capacity to store data. Arrays of disk drives have been attempted in the prior art, however, they require special foreground or background processing to distribute the data in such a fashion as to take advantage of the array architecture. Thus, there is a need in the art for a high capacity disk drive capable of transferring large amounts of data at high speed, yet not requiring special interfaces for the host computer.